Position reporting devices are frequently used to locate and report the position of a person or object. A typical position reporting device combines a navigation system such as a Global Positioning System (GPS) module with a mobile communications system such as a cellular modem to determine the position or geographic location of a person or an asset being tracked and report its position to a tracking facility. Position reporting devices are used in a variety of systems in which timely position information is required such as fleet tracking and asset recovery systems.
Fleet tracking systems allow a user to monitor the position of a vessel or vehicle carrying a position reporting device. For example, the course of a vehicle being tracked can be inferred using successive position fixes sent by the position reporting device. The phrase “position fix” refers to a process of determining an unknown location using a fixed reference point or points. In a similar manner it can be inferred that the vehicle is not moving when successive position fixes report the same position. Fleet tracking systems are commonly used by delivery services for the routing and dispatching of vehicles. Asset recovery systems report the position of stolen or missing property (e.g., a stolen car) to a service provider or to the police in order to facilitate recovering the property.
However, many potential users find the cost of position reporting devices prohibitive compared to the value of the asset being tracked. Many position reporting devices have a manufacturing cost in the range of $200-$300 and a market price in the range of $500-$600. Thus, the use of position reporting devices has typically been limited to high value items such as cars or other vehicles.
Another drawback associated with position reporting devices is the amount of power they consume. While battery powered position reporting devices do exist, the amount of power they consume when turned on necessitates frequent battery changes in order to continue operating. This makes using position reporting devices inconvenient to some users in that they require an excessive amount of maintenance to continue operating.
Moreover, many position reporting devices utilize information that they access from satellite based positioning systems such as GPS. While satellite based positioning works very well in open space locational environments, some devices face constraints in achieving a valid and reliable (e.g., accurate, precise, etc.) geographic position fix using satellite based position information in environments other than such open spaces. For instance, when operated in a dense, urban cityscape type environment, it can be difficult for some devices to achieve a valid satellite based position fix. While some of these devices can eventually arrive at a valid geographic fix solution based exclusively on satellite based locational information, achieving it can be costly in terms of computational and/or networking resource usage and/or power consumption. Where a valid fix can be achieved under such constraints, calculating the solutions to achieve the fix can require an inordinate amount of time. This can be unacceptable in some situations.